At around 9:26 in the video it’s explained that one can tell that a parameter is optional by googling it’s docs – this isn’t entirely correct as you can see if a param is optional based on whether it has an equal sign in the method signature tooltip. (Look for the = in the tooltip, shown as UClass *Classfilter = (UClass *) 0)
Maybe prof will reveal this later, but I wanted to point it out.